Foreign Minister Murray McCully is headed for New York to lobby international counterparts over New Zealand's bid for a seat on the United Nations Security Council.

Mr McCully confirmed he would be in New York to deliver a speech to the UN General Assembly and would also be using the opportunity to try and pick up more votes in support of New Zealand's bid for a seat in 2014.

He would not say how many countries had so far pledged support but said he was "comfortable with the progress we are making".

But he acknowledged it was tough up against Spain and Turkey, who are also seeking election to the two available seats.

"There are those who argue you can only buy a seat on the Security Council. If that's the case we certainly wouldn't get there; we have to stand on our own credentials. I think they are particularly good credentials but we need to work very hard to get there."

New Zealand has served three times on the Security Council, most recently in 1993-94.